1. Field of the Invention
The present invention generally relates to initialization methods, reproduction methods, computer-executable programs, recording media, data structures, information recording apparatuses, and information reproducing apparatuses, and more particularly to an initialization method for initializing an information recording medium, a data structure used in the initialization method, a reproduction method and an information reproducing apparatus for reproducing data from an information recording medium, an information recording apparatus for recording data to the information recording medium, a program product for use with the information recording apparatus, and a computer-readable recording medium recorded with a program.
2. Description of the Related Art
Since an optical disc such as a CD (Compact Disc), a DVD (Digital Versatile Disc), and a like used as an information recording medium to record data has becomes popular, an optical disc apparatus has been widely used as an information reproducing apparatus for recording data to the optical disc and reproducing data from the optical disc. An information recording apparatus and an information reproducing apparatus may be collectively called a drive unit.
A CD-R (Compact Disc Recordable) and CD-RW (Compact disc ReWritable) are used as a recordable CD, and a DVD-R (Digital Versatile Disc Recordable), a DVD+R, a DVD-RW, and a DVD+RW are used as a recordable DVD. Data are recorded and reproduced in accordance with a respective predetermined standard.
For example, for an initialization process (format process) of the optical disc, a background format process is applied for the DVD+RW. The background format process is different from a conventional format process used for the CD-RW. Just the main portion is formatted (hereinafter, called “initialize”). Dummy data are successively recorded to other portions from the beginning of data zone when there is no record request or reproduction request from an upper apparatus. Since this background format process can be cancelled at any time, the background format process is cancelled and the optical disc can be ejected. In this case, when a temporary read-out is additionally provided, the background format process can be compatible with the DVD-ROM. Also, without providing the temporary read-out, the optical disc can be ejected. In this case, recorded areas and non-recorded areas are mixed in the data zone. In the background format process, information showing a location where the format process ends is stored in a last written address (hereinafter, called LWA). Thus, the background format process can be resumed from an area indicated by an address next the LWA.
In the background format process, after the initialization ends, it is possible to record and reproduce data for whole area of the disc. Accordingly, when user data are recorded with respect to a non-format area, in order for a subsequent background format process not to rewrite data, most optical disc apparatuses have bitmap information used to determine whether an area is the non-recorded area or the recorded area.
By using the bitmap information, it becomes possible to determine whether the area is the non-recorded area or the recorded area. However, it cannot be determined that data recorded in the recorded area are dummy data. For example, in a case in that the reproduction request is made for an area where the format process ends and data recorded in the area cannot be normally reproduced, even if the data recorded in the area are dummy data, a reproduction error is informed. Then, a process at a user side is inconveniently interrupted. Moreover, disadvantageously, the optical disc can be determined as a disc having a read-out defect.
Accordingly, Japanese Laid-open Patent Application No. 11-86418 discloses to provide additional bitmap information used to determine whether data recorded in an area is the user data or the dummy data in addition to the bitmap information used to determined whether the data recorded in the area is the non-recorded area or the recorded area. The above-described problem can be solved by using this additional bitmap information. However, it is required to have two kinds of bitmap information. As a result, a larger capacity of memory configured in the optical disc apparatus is required and becomes a higher expense. In addition, since two kinds of bitmap information are individually checked, a performance can be degraded.